Posted on 08/02/2005 4:00:39 PM PDT by Graybeard58
It might sound preposterous, like astrology, to suggest that galactic events help determine when North America is or isn't buried under immense sheets of ice taller than skyscrapers. But new research suggests the coming and going of major ice ages might result partly from our solar system's passage through immense, snakelike clouds of exploding stars in the Milky Way galaxy.
Resembling the curved contrails of a whirling Fourth of July pinwheel, the Milky Way's spiral arms are clouds of stars rich in supernovas, or exploding stars. Supernovas emit showers of charged particles called cosmic rays.
Theorists have proposed that when our solar system passes through a spiral arm, the cosmic rays fall to Earth and knock electrons off atoms in the atmosphere, making them electrically charged, or ionized. Since opposite electrical charges attract each other, the positively charged ionized particles attract the negatively charged portion of water vapor, thus forming large droplets in the form of low-lying clouds. In turn, the clouds cool the climate and trigger an ice age -- or so theorists suggest.
In that regard, researchers are finding correlations between the timing of Earth's ice ages and epochs when our solar system passed through galactic spiral arms.
The latest evidence appears in a recent issue of Astrophysical Journal. The article is the result of an unusual collaboration between an astronomer, Professor Douglas Gies of Georgia State University's Center for High Angular Resolution Astronomy, and a 16-year-old student at Grady High School in Atlanta, John Helsel. They report the results of their effort to determine how the sun has moved through the galaxy over the last half-billion years.
By making a variety of assumptions about the rate of solar motion and the distribution of spiral arms in the galaxy -- which are difficult to map because galactic dust and foreground stars get in the way -- Gies and Helsel conclude that "the sun has traversed four spiral arms at times that appear to correspond well with long-duration cold periods on Earth."
"This," they continue, "supports the idea that extended exposure to the higher cosmic-ray flux associated with spiral arms can lead to increased cloud cover and long ice age epochs on Earth."
Gies and Helsel's article is the long-term result of a project that Helsel began working on "as a science fair project," Gies says. Gies, 50, is a neighbor of Helsel's. Gies had previously "developed a scheme to model the motion of some massive stars in the galaxy," and when Helsel approached him for guidance on the science fair project, their "conversation quickly focused on studying the sun's motion and encounters with spiral arms in the galaxy."
A veteran investigator of the galaxy-ice age hypothesis is astrophysicist and assistant professor Nir Shaviv, 33, of Racah Institute of Physics at Hebrew University in Jerusalem, who was previously a postdoctoral researcher at the California Institute of Technology. He has reanalyzed other scientists' previously published data on meteorites, which contain mildly radioactive isotopes -- fragments of atoms that were altered by cosmic-ray bombardments over millions of years while the meteorite was still hurtling through space. Based on the ages of different isotopes, he concludes the cosmic-ray bombardments were most intense during past epochs when Earth is believed to have passed through known spiral arms.
An alternate but related hypothesis of ice ages suggests that Earth occasionally passes through huge interstellar clouds of hydrogen gas. Such clouds are common in the spiral arms. According to this hypothesis, the interstellar clouds chemically soak up oxygen molecules in Earth's atmosphere, dramatically lowering the levels of the gas ozone, which normally heats the atmosphere by trapping infrared radiation.
Thanks. Problem with uniformitarian causes is, that they aren't. :') That's why there are so many such models. Earth's closest to the Sun in January I think, which makes northern hemisphere winters a bit warmer, and furthest in July I think, making southern hemisphere winters a bit cooler. But most of the southern hemisphere is ocean, okay, I'm boring even myself...
"Let me be the first to suggest that this kid is wasting his time in high school. "
When I entered University I took an intensive first year mathematics progrom of first and second year courses becuase I had a high second class average in high school
In my second year linear class I struggled in the first two months of the fall semester and then one day this guy showed up in class who I hadn't seen before.
Turns out he was a math genius and the son of a mining engineer from Trail BC who had attented advanced mathematics camps since he was 13.
He showed up one day because he had an interesting proof he wanted to show the prof. When he was finished baffling the prof with his proof he left. Everyone in the class was slack jawed.
That day was the end of my mathematics career.
Later I found out he got bored with mathematics and joined the theater department.
I hope you find it as clear & well written as I did. I regularly pass out copies of that book, and I buy them from Amazon. Sorry about driving the price up.
Make sure you read the abstract before the book. It was so concise and on target, that I can show people that abstract and say, "This is what the book is about."
I have a mind to buy non-exclusive rights for that book. I wonder how much such a thing would cost?
Except for the drifting continents part.
The sun [and earth] rotate about the Milky Way in 200 million years. If there is a particular dusty spot in our spiral arm our inclination to the plane would swing us by that spot twice in 100 million years. That puts these events on the average 50 million years apart. Does that match up with the frequency of ice ages?
"Except for the drifting continents part."
***Actually, the tectonic plate theory is instructive here. Most scientists didn't accept that theory at the time it was proposed -- it was too outlandish. Eventually, those scientists died off and were replaced with a new generation of open-minded scientists who gave it a whirl and verified much of the theory. I see that a lot of catastrophism was summarily dismissed when it was first proposed by guys like Velikovsky, but now it is readily accepted as part of different cosmology theories.
"... any new theory (especially one which makes outstanding claims) has to have established scientific laws to support it."
***We both agree, sorta. I would readily accept your statement if the word "law" were substituted with the word "evidence". That word, "law" causes trouble in these kinds of discussions because people start using it as if it really did mean "law". In scientific method, a law is just an observation. Newton's law of gravity doesn't mean everything has to "obey" that law, it is just an observation of how gravity behaves, with a nifty mathematical description. Note that we do not call it the "theory of gravity" because a theory explains why... and we really don't know what causes gravity at this point. When physicists started noticing that at the atomic scale, Newtonian "laws" were no longer applicable, a new observation was introduced as a correction factor to physics, thanks to Einstein. It was widely discussed and supported because there were observations that no longer fit the Newtonian mold and, it was brilliant physics. Exactly what scientific "laws" did NOT support plate tectonics at the time it was proposed?
"I've read "Worlds in Collision" by Velikovsky and all of his physical predictions are invalidated by the well established laws of physics that I've studied up through college."
***I read it too, and I also studied somee physics in college, welcome to the club. Again I would quibble with your use of the word "law". I agree that Velikovsky's predictions and theory did not pan out for the most part. But his predictions were not invalidated by "laws" of physics, they were invalidated by direct empirical observation. Some people thought Velikovsky was ahead of the game when it was verified that Venus was indeed very hot (contemporary cosmology said that it would be a cold planet), but he was probably just lucky.
"Just as one example, his theory that Venus could pass by the Earth and cause the Earth's rotation to stop and then restart is nonsense according to the laws of thermodynamics and conservation of angular momentum, among others, and there are no known forces that could explain such an event."
***Again you're using the word "law" in a way that doesn't really help the discussion along. If I do the "law = observation" substitution, I would probably agree with you. The fact that there are no KNOWN forces which could explain it is exactly the point. It is postulated as an UNKNOWN force, possibly stronger than gravity, which is after all a relatively weak force. But that's one thing I like about bold theories -- they should be easy for experts to point out the obvious flaws. I'm no cosmologist.
Thanks for the ping.
I seriously doubt that earth CROSSES spiral arms of the galaxy, instead of drifting along with the flow that causes the spiral arms.
[Dewey McLean is one of the most stubborn opponents of the Alvarez model; he has mellowed somewhat in recent years regarding his claims that the late Luis Alvarez tried to run him out of academia]
New Developments Regarding the KT Event and Other Catastrophes in Earth History
Dewey McLean
http://filebox.vt.edu:8080/users/dmclean/fileboxmigration/artsci/geology/mclean/Dinosaur_Volcano_Extinction/pages/law_natr.pdf
Proposed law of nature linking impacts, plume volcanism, and Milankovitch cycles to terrestrial vertebrate mass extinctions via greenhouse-embryo death coupling
Dewey McLean
http://filebox.vt.edu:8080/users/dmclean/fileboxmigration/artsci/geology/mclean/Dinosaur_Volcano_Extinction/pages/ghreplon.html
Chandler's Wobble Causes Earthquakes, Volcanism, El Nino, and Global Warming
Michael Wells Mandeville | 2004 | Michael Wells Mandeville
Posted on 01/18/2005 8:58:05 PM PST by IGBT
http://www.freerepublic.com/focus/f-news/1323583/posts
another oldie
Looks like an interesting read. :)
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